[Cbor] tag optionality and dCBOR

[Laurence Lundblade <[e-mail]>]

Section 4.2 of 8949 discussed tags in relation to deterministic encoding and around 5 minutes into the dCBOR video this is discussed.

I’d like to drive a wedge between serialization variability (e.g. integer lengths, map sorting) and tag optionality and would like there to be no requirements in dCBOR around tag optionality. I think tag optionality is a protocol/application design characteristic.

This is a little bit of a round about way to highlight this — A protocol that sends three integers (e.g. red, green and blue for a pixel) could use an array where red is first, green is second and blue is third. Or it could use a map and label the three integers. I expect dCBOR to be completely silent on this choice. It’s an application/protocol design issue with nothing to do with serialization variability.

I think the choice of whether to identify items in a protocol/application by tag is of the same nature.

I also think that discussion of tag optionality should probably not be in section 4 of 8949. It’s not really a related to serialization.

LL